2002 Annual Report Horticulture Section |
Dickinson
Research Extension Center
1089 State Avenue Dickinson, ND 58601 |
Xeriscape Ornamental Perennial Grass Trial for Low Water Use Landscaping
Llewellyn L. Manske and Jerry C. Larson
Range
Scientist, NDSU, Dickinson Research Extension
Center
Extension
Agent, NDSU, Extension Service, Stark-Billings County
Western North America has increasing difficulty in providing adequate quantities
of clean water for domestic use. A large portion of western municipalities'
water supply is used for watering lawns, gardens, and landscape plants. Traditional
landscaping frequently selects Kentucky bluegrass lawns and ornamental plants
that require large amounts of water to remain beautiful. Several agencies and
institutions joined Denver Water and the Associated Landscape Contractors of
Colorado in 1981 to develop the concept of "Xeriscape" gardening. Alternatives
to traditional techniques are being examined to develop landscapes that are
harmonious with the local environmental conditions and use less water. Homeowners
in western North Dakota have experienced the high costs of using domestic water
for traditional landscape plants and have become aware of the need for alternative
landscaping plants. Grass species in this trial are being tested and examined
for use as plant material in low water use landscaping.
The purpose of Xeriscape gardening, or low water use landscaping, is to conserve
expensive, precious domestic water by following seven simple commonsense principles.
Low
water use landscaping achieves the desired goal of conserving water, money,
leisure time, and precious resources while providing healthy, beautiful landscapes
that add value to property. Xeriscape gardening combines landscaping with conservation.
Methods
This multi-year trial was designed to test and evaluate native grasses and adopted
horticultural grasses as low water use ornamental landscape plants in western
North Dakota. Thirteen native grasses and eleven horticultural domesticated
grasses (Table 1) were included in this study. The research
plots are located at the Dickinson Research Extension Center. These plots are
managed with minimum maintenance, little supplemental irrigation water, no fertilizer,
no herbicides after plot establishment, and hand roguing of weeds when necessary.
The study consisted of three replications (Table 2). The grass
plants were evaluated for vigor, ornamental value, seedhead aesthetics, color,
and height. Vigor, ornamental value, and seedhead aesthetics were rated on a
scale of 0-5 (Table 3). Color was recorded as one of twelve
colors (Table 3). Total plant height was recorded as one of
three height categories (Table 3). The twenty-four grass entries
were randomly placed in plots in three replications (Table 4).
Two evaluators rated each grass replication during initiation, early, mid-1,
mid-2, late, and post growing-season periods.
Results
Mean evaluation ratings of grass entries are shown in Tables 5-9
for initiation, early, mid-1, mid-2, and late growing-season periods for 2001,
respectively. Plants on replication plots of little bluestem, buffalo grass,
Indiangrass, Canada wildrye, and sweetgrass died during the first year of the
trial as a result of weakened condition caused by the plants' being covered
by wood chips for several days and not receiving additional attention to assist
the plants' recovery. These plants were replaced in the spring of 1999. Plants
that expired from environmental conditions or natural causes were not replaced.
The mean values of the evaluation ratings were determined for each growing-season
period. Some ratings are reported with two mean values. The first value includes
data from all three replications, and the second value includes data from only
the active replications.
Most of the grass entries increased in vigor and ornamental value from initiation
of growing-season, through mid-, and to late-season periods (Table
5-9). Several grass entries had medium to high vigor and ornamental value
ratings during the initiation of growing-season period, and one entry--sweetgrass--had
seedheads present in mid May (Table 5). Vigor and ornamental
value decreased for most grass entries after the late growing-season period
(Table 9). Several grass entries--blue grama, little bluestem,
buffalo grass, sideoats grama, big bluestem, sand bluestem, prairie sandreed,
Indiangrass, switchgrass, prairie cordgrass, sweetgrass, feather reed grass,
ribbon grass, blue lyme grass, red switchgrass, autumn red, Altai wildrye, and
pampas grass--had medium to high vigor and ornamental value ratings during the
late growing-season period (Table 9). Most of the grass entries
tended to have high seedhead aesthetics value ratings during the period from
head-emergence to seed-development stages (Table 5-9). Several
grass entries--blue grama, little bluestem, buffalo grass, sideoats grama, big
bluestem, sand bluestem, prairie sandreed, Indiangrass, switchgrass, prairie
cordgrass, Canada wildrye, feather reed grass, blue lyme grass, red switchgrass,
autumn red, Altai wildrye, and pampas grass--had medium or high attractiveness
of seedheads after reaching full maturity and during the late growing-season
period (Table 9).
A few grass entries--sand love grass, giant silver banner grass, and zebra grass--had
three or more sample periods with low vigor ratings and low ornamental values
(Table 5-9). Several grass entries--blue grama, little bluestem,
buffalo grass, big bluestem, sand bluestem, prairie sandreed, Indiangrass, switchgrass,
prairie cordgrass, sweetgrass, feather reed grass, ribbon grass, blue lyme grass,
red switchgrass, autumn red, Altai wildrye, and pampas grass--had three or more
sample periods with high vigor ratings and high ornamental values (Table
5-9).
Most of the grass entries had distinctive attractive shades of green during
the early, mid, and late growing-season periods (Tables 5-9).
Many of the grass entries completed senescence during the late and post growing-season
periods, displaying attractive shades of red, purple, or yellow before turning
tan (Table 9).
The height categories for the grass entries (Table 10) were
determined when the plants were mature and the seedheads had reached maximum
height. Some of the grass entries grew relatively tall during the growing season
of 2001. The grasses with seed heads taller than 6 feet were big bluestem, sand
bluestem, prairie sandreed, prairie cordgrass, and pampas grass. Mature height
of a plant is important in landscape design. The trial included three short-grass,
thirteen mid-grass, and eight tall-grass entries.
Discussion
This is the fourth year of a multi-year trial designed to test and evaluate
grass entries for use as ornamental plants for low water use landscaping. Most
of the grass entries show positive potential for use as low water use landscaping
plants. A few grass entries had one or more sample periods with low ratings,
but these grasses should not be dismissed as landscape plants yet because the
plants may improve. Some of the other grass entries may not maintain their moderate
or high value ratings for the long run under these low maintenance and low supplemental
water conditions.
Low water use landscaping, which uses native and/or adopted horticultural plants,
is an important alternative to traditional landscaping, which uses plants that
require large amounts of supplemental domestic water to remain beautiful. The
results of this trial will assist homeowners in selecting ornamental perennial
grass plants for use in their low water use landscaping.
The ornamental grass research plot at the Dickinson Research Extension Center
has attracted lots of public interest. It is evident that the use of ornamental
grasses in southwest North Dakota is steadily increasing. Local greenhouses
and nurseries document this interest through increased sales of ornamental grasses.
This acceptance is also evident through a windshield survey driving through
Dickinson and surrounding areas.
Acknowledgment
The authors thank Ron Smith, NDSU Extension Horticulturist, Fargo, for providing plugs of horticultural adopted grass species plant material #13 to 20, for assisting with plot establishment, and for providing consultation during the development of this research project. We thank Craig Armstrong for providing plugs of horticultural adopted grass species plant material #22 and 23 and for providing advice on plot management. We thank USDA Plant Materials Center, Bismarck, for providing plugs of native species plant material #1 to 12. We thank Mike Knutson, USDA Plant Materials Center, Bismarck, for selection, collection, and delivery of native species plant material plugs and for assistance with plot establishment. We thank Jon Stika, NRCS, Area Agronomist, Dickinson, for making arrangements for native species plant material and for assistance with plot establishment. We thank James Nelson, DREC Animal Scientist, Dickinson, for preliminary preparation of plot area and for providing and spreading wood chips. We are grateful to Sheri Schneider for assistance in production of this manuscript. We are grateful to Amy M. Kraus and Naomi J. Thorson for assistance in preparation of this manuscript.
Reference Literature
Denver Botanic Gardens. No date. Water-smart gardening. Brochure. Denver
Parks and Recreation Department, Denver, CO.
Denver Water. 1996. Xeriscape plant guide. American Water Works Association.
Fulcrum Publishing, Denver, CO.
Denver Water. No date. Discover xeriscape. Pamphlet. Xeriscape Colorado
Inc., Denver, CO.
Denver Water. No date. Efficient irrigation systems at work. Pamphlet.
Office of Water Conservation, Denver, CO.
Hill, L., and N. Hill. 1995. Lawns, grasses and ground covers. Rodale
Press, Emmaus, PA.
Plant Materials Center. 1997. Native grasses for prairie landscaping
in the Northern Great Plains. Brochure. USDA Natural Resources Conservation
Service, Bismarck, ND.
Report
Tables
Table 3. Ratings scales used in the evaluation methods of this trial. | |||||
Plant Vigor Ratings Scale |
|||||
5 | 4 | 3 | 2 | 1 | 0 |
robust vigor |
medium vigor |
low vigor |
dead |
Ornamental Value Ratings Scale |
|||||
5 | 4 | 3 | 2 | 1 | 0 |
high value |
medium value |
low
value |
zero
value |
Seedhead Aesthetic Ratings Scale |
|||||
5 |
4 | 3 | 2 | 1 | 0 |
high attractiveness |
medium attractiveness |
low attractiveness |
not
present |
Color Ratings |
||
1. Drying | 5. Bluegreen | 9. Yellow Green |
2. Dark Green | 6. Light Blue | 10. Light Red |
3. Green | 7. Dark Blue | 11. Purple |
4. Light Green | 8. Gold yellow | 12. Tan |
Height Ratings Categories |
|
Short grass | 0.5 to 2.0 feet |
Mid grass | 2.0 to 3.0 feet |
Tall grass | 3.0 to 7.0 feet |
Rep. #1 West |
Rep. #2 Middle | Rep. #3 East | |||
1
Blue |
3
Buffalo |
23
Blue |
8
Indiangrass |
18
Zebra |
16
Sand |
4
Sideoats |
12
Sweetgrass |
11
Canada |
9
Switchgrass |
21
Altai |
20
Autumn |
14
Ribbon |
15
Blue |
24
Green |
7
Prairie |
6
Sand |
23
Blue |
2
Little |
11
Canada |
17
Giant
silver |
14
Ribbon |
3
Buffalo |
5
Big |
5
Big |
6
Sand |
4
Sideoats |
22
Pampas |
19
Red |
2
Little |
7
Prairie |
8
Indiangrass |
16
Sand |
10
Prairie |
22
Pampas |
17
Giant
silver |
13
Feather |
16
Sand |
2
Little |
19
Red |
10
Prairie |
13
Feather |
9
Switchgrass |
10
Prairie |
12
Sweetgrass |
5
Big |
8
Indiangrass |
4
Sideoats |
17
Giant
silver |
18
Zebra |
15
Blue |
21
Altai |
1
Blue |
15
Blue |
19
Red |
20
Autumn |
13
Feather |
1
Blue |
7
Prairie |
12
Sweetgrass |
21
Altai |
23
Blue |
18
Zebra |
3
Buffalo |
9
Switchgrass |
11
Canada |
22
Pampas |
24
Green |
20
Autumn |
6
Sand |
24
Green |
14
Ribbon |
Split
values: includes 3 reps./only active reps.
Evaluation
vigor:
Low 11, 16, 17, 18, 19, 23
High
3, 10, 12, 13, 14, 15, 20, 21, 22
Ornamental
value: Low 2, 4, 6, 9, 11, 16, 17, 18, 19, 23
High
7, 10, 12, 13, 14, 15, 20, 21, 22
Split
values: includes 3 reps./only active reps.
Evaluation
vigor:
Low 16, 17, 18
High
1, 3, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 19, 20, 21, 22
Ornamental
value: Low 11, 16, 17, 18, 23
High
1, 4, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 19, 20, 21, 22
Split
values: includes 3 reps./only active reps.
Evaluation
vigor:
Low 16, 18, 23
High
1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 19, 20, 21, 22
Ornamental
value: Low 16, 18, 23
High
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 19, 20, 21, 22
Split
values: includes 3 reps./only active reps.
Evaluation
vigor:
Low 16, 18
High
1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 19, 20, 21, 22
Ornamental
value: Low 16, 18
High
1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 19, 20, 21, 22
Split
values: includes 3 reps./only active reps.
Evaluation
vigor:
Low 16, 18
High 2, 3, 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 19, 20, 21, 22
Ornamental
value: Low 16, 18
High
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 19, 20, 21, 22
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